Lens adapter device, particularly lens protecting device

ABSTRACT

A lens attachment device is provided for use with a camera having a housing, the housing having at least one modular insert compartment, wherein each modular insert compartment is adapted to receive an insert having an optical device. The lens attachment device includes a lens protection device having a circumferential surface, a holding frame adapted to fit within the modular insert compartment of the housing. The holding frame holds the lens protection device. The lens attachment device further includes a motor housing for containing an electromechanical drive, and a drive wheel operable to rotate the lens protection device, wherein the electromechanical drive is operable to rotate the drive wheel.

REFERENCE TO RELATED APPLICATIONS

This application claims priority to PCT/DE2007/001600, filed Sep. 10, 2007, and DE 10 2006 042 793.9, filed Sep. 8, 2006, the entire contents of each of which are incorporated herein in their entirety.

FIELD OF THE INVENTION

The invention relates to a lens attachment device, in particular a lens protection device, for protection from approaching particles of rain or snow, in accordance with the kind defined more closely in the preamble of claim 1.

PRIOR ART

The use of cameras, and in particular of movie cameras, frequently takes place under unfavorable conditions in which the camera lens has to be protected from e.g. an adhesion of approaching particles such as raindrops, snowflakes or also midges to ensure a sufficient image quality.

It is known from practice to position a fast-rotating glass disk in front of the lens for this purpose so that all approaching particles are hurled away in the direction of the circumference of the disk by the centrifugal force produced by the rotating glass disk and thus do not further impair the image quality.

Such a centrifugal lens protection device is known e.g. from U.S. Pat. No. 3,879,742 in which a surveillance camera is located in a weatherproof housing having a rotatable disk.

U.S. Pat. No. 5,223,880 describes an accessory for cameras in the manner of a centrifugal lens protection device, with the disk being made as a unit with a rotor of a magnetic motor, said unit being fastened to the free end of the lens.

U.S. Pat. No. 5,315,333 shows the attachment of a rotating disk to a camera housing via carriers so that the disk is arranged in front of the camera, but is not connected thereto.

A further such arrangement of a rotating disk in front of the lens is disclosed in U.S. Pat. No. 6,731,867.

It is, however, disadvantageous with all of these lens protection devices that the use with further lens attachments, in particular a matte box, is made difficult and that in part substantial, time-consuming conversion work is necessary on a change of an optical lens attachment such as a filter.

An example for a matte box for a movie camera is shown in DE 35 23 039 A1, wherein a frame is provided for the connection to the camera in front of the lens, a light shade is provided for engagement with the camera lens and at least one filter is provided which is arranged between the frame and the light shade. A plurality of filter holding modules are provided with matching dovetail slots at their front and rear surfaces to enable a fast assembly and release of any number and any kind of filter holder modules and a connection to the frame. A latching mechanism is provided in releasable form at each module to hold each module aligned with the adjacent module and in the correct position.

A further matte box, also known as a compendium, which has a modular structure, is known from the German utility model DE 20 2005 004 067 01. This matte box has a base matte box comprising a base matte box carrier which is connected at its one side to a lens hood or sun shade having selectively fixed or pivotable blades and at whose rear side a plurality of filter holding modules are arranged which are connected via quick-fastening devices at their front and rear sides to one another and to the lens hood. The number of filter holding modules can be determined by the connection of the individual filter holding modules via their front and rear sides and individual filter holding modules can be replaced or can be removed from the base matte box.

Further developments of these matte boxes are available on the market, with a matte box offered under the trade name “ARRI MB-14” being mentioned only by way of example.

DISCLOSURE OF THE INVENTION Technical Object

It is the object of the present invention to provide a lens attachment device for a camera, in particular for protection from approaching particles such as rain or snow, having a disk which can be set into rotation, with the installation and operation of the device being very largely simplified with further attachment components in front of the lens, in particular in the manner of a matte box.

Technical Solution

This object is achieved in accordance with the invention by the features of claim 1.

The invention thus provides for designing a lens attachment device, in particular a lens protection device for protection from approaching particles such as rain or snow, for cameras having a disk which can be set into rotation such that the disk is arranged in a holding frame which is made as an insert of a carrier for components influencing image properties in front of a camera lens.

Advantageous Effects

Since a lens attachment device having a disk which can be set into rotation, in particular for protection from approaching particles, is made as a matte box insert or compendium insert having a holding frame suitable for insertion into such a carrier, both the installation and the operation of such a lens attachment device are considerably simplified with respect to known solutions.

The holding frame can in this respect have the shape of a filter frame or can represent a rotatable filter stage so that the lens protection device can optionally be inserted into a conventional carrier device or a matte box.

The design of the lens attachment device in accordance with the invention as a module which can be inserted on or into a matte box at any desired position enables complex construction measures for the avoidance of such a matte box to be dispensed with. The saving of corresponding construction components furthermore has a positive effect on a low weight of the matte box equipped with the device in accordance with the invention and thus of the camera as a whole.

In this respect, the invention enables the design of the combination of rain protection and filter carrier with a weight which amounts to approximately half the weight of conventional constructions.

It furthermore allows a fast conversion of components influencing the image properties in front of the camera lens.

A simple cleaning is furthermore possible with a mechanical closure device for the disk.

The invention also enables the use of comparatively large diameters of the rotating disk, e.g. disks having a diameter of 118 mm instead of 95 mm in solutions from the prior art with otherwise comparable general conditions.

Such a lens protection device which in principle works like a conventional rain repelling device and rotates e.g. at 3000 to 3500 revolutions per minute is particularly suitable with movie cameras, but it can also be used with photographic cameras, in particular with so-called technical cameras.

The disk of the lens attachment apparatus in accordance with the invention can be made as a neutral cover glass disk for use as only a lens protection device. The term “glass” in this respect as in all the present application, is to be understood in its widest sense as a material for an at least regionally transparent disk, with the term “glass” not being restricted to mineral glass, but also including plastics.

Additionally or alternatively to its function as a protective element, the disk can, however, also be made as a disk causing an optical effect. It can, for example, act as an optical filter which selects the incident radiation in accordance with specific criteria, e.g. in accordance with the wavelength, the polarization state or the direction of incidence.

Provision can also be made within the framework of the invention that two or more disks are arranged in the holding frame of the lens attachment device in accordance with the invention.

At least one of these disks can serve the generation of optical effects on their rotation in this connection. If two disks arranged in a holding frame are each made as polarization filters, a diaphragm effect can be achieved by a folding toward one another of the polarization filters rotating in different directions which ranges up to a closure of the camera lens or absolute light-proofness with a 90° crossing of the polarization disks.

The drive of the at least one disk is expediently integrated into the holding frame of the disk or set onto it in the lens attachment device in accordance with the invention.

In a very simple embodiment of the invention, the drive is made with an electric motor which drives the disk via a wheel rolling off at the disk rim of the rotating disk.

The motor and the drive of the rotating disk will preferably be configured as a whole by the person of ordinary skill in the art so that on the use of the rotating disk only as a protective glass, a motor with a particularly high speed can be selected, whereas on a function of the disk as an image-creative element, in particular the positional precision of the disk can be of importance so that here a regulated motor with a downstream transmission is preferably used.

While it can be sufficient with a simple embodiment of the lens attachment device in accordance with the invention that the drive is only connected to the camera for the power supply, provision can be made in a further development of the invention, in particular with a disk having an optical effect, that the motor of the drive is speed-regulated in dependence on output signals of electronics of the camera and is thus controlled, for example by a diaphragm control of the camera.

The support of the at least one disk in the holding frame can take place in a simple embodiment via resiliently supported rollers at which the rotating disk rolls off in its rim.

The outer geometrical design of the holding frame is dependent on the matte box and its filter holding modules with which the lens attachment device in accordance with the invention should be compatible.

If the holding frame of the disk is made with corresponding connection devices which comprise the individual modules of the matte box for connection to one another, the lens attachment device in accordance with the invention with its holding frame itself can itself represent a module which can be inserted into or set onto the matte box at any desired position.

The connection devices for the connection to other modules of the matte box can in this respect represent dovetail devices at the front side and/or rear side of the holding frame by means of which push-and-click connections can be established with the adjacent module.

Further advantages and advantageous aspects result from the drawing, the description and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Three embodiments of a lens attachment device in accordance with the invention which is compatible with a filter holding module of a matte box of conventional design are shown in the drawing and will be explained in more detail in the following description.

There are shown:

FIG. 1 an exploded representation of a first embodiment of a lens attachment device made as a lens protection device;

FIG. 2 an exploded representation of a second embodiment of a lens attachment device made as a lens protection device;

FIG. 3 a rear view of the lens attachment device of FIG. 2 without a rear cover;

FIG. 4 a rear view of the lens attachment device of FIG. 2 with a rear cover;

FIG. 5 a front view of the lens attachment device of FIG. 2;

FIG. 6 a side view of the lens attachment device of FIG. 2; and

FIG. 7 an exploded representation of a third embodiment of a lens attachment device made as a lens protection device.

EMBODIMENTS OF THE INVENTION

A respective lens attachment device 1, 1′, 1″ is shown in the Figures of the drawing which serves as a lens protection device for the protection of a camera lens and of components influencing image properties attached in front thereof from approaching particles such as rain, snow or dirt.

The lens attachment device 1, 1′, 1″ is in this respective made as an insert of a carrier for components influencing image properties in front of a camera lens of a movie camera, with this carrier forming a conventional production matte box of modular structure, e.g. in accordance with the matte boxes quoted as prior art above.

The same reference numerals were used for components of the same respective functions in the representation of the embodiments of the lens attachment device 1, 1′, 1″ for reasons of clarity.

The lens attachment device 1, 1′ in each case has a disk 2 made as a cover glass disk which is rotatably supported in a holding frame 4.

The holding frame 4 is matched to the filter module of the matte box with respect to its outer dimensions and geometry, with the holding frame 4 being insertable into said matte box instead of a front filter stage.

In the assembled state, the holding frame 4 is covered on the front side remote from the camera by a front cover 6 and on the rear side facing the camera by a rear cover 8, said covers in each case having a circular cut-out matched to the size of the disk 2.

The installation of the covers 6 and 8 at the holding frame 4 takes place in a simple manner in the present case via screw connections by means of countersunk screws 10.

In the installed state, the rim of the disk 2 is encompassed by four guide wheels 12 which are resiliently supported at the holding frame 4 in the radial direction and which each have a wheel hub 14 which is arranged at the holding frame 4 via a bearing screw 16 and two collar bearings 18, 19 made as grooved ball bearings.

The upper guide wheels are adjusted manually in the embodiments shown. For this purpose, the bearing screws 16 can be loosened and the guide wheels 12 can be guided to the disk 2 accordingly. The lower guide wheels are not adjustably fixed to the holding frame 4 in the present case and are likewise supported at the holding frame 4 in two-fold manner via collar bearings 18, 19 formed as grooved-ball bearings.

In addition to the four guide wheels 12 arranged with an equal spacing from one another and each associated with one corner of the holding frame 4, a drive wheel 20, which is connected to an electric motor drive 22, engages in the central upper region within the holding frame 4 at the rim of the disk 2.

The connection between the electric motor 22 and the drive wheel 20 takes place via an upper driver plate 23 and a lower driver plate 25.

The electric motor drive 22 is formed in the present case by a miniature DC motor which is guided at its periphery through a corresponding opening of a carrier board 24 and is received in a housing 26 which represents a cap and which forms a rear covering of the holding frame 4 above the rear cover 8. The drive 22 which is furthermore resiliently supported in the radial direction by means of springs, not shown, is thus integrated into the holding frame 4.

A resiliently supported pusher 27 is provided for the operation of the electric motor 22. A protective ring 28 serving as a brake is furthermore arranged at the rear side of the electric motor 22 via which the drive wheel 20 connected to the electric motor 22 can be held so that the disk 2 is locked. Such an operating state is advantageous, for example, for the cleaning of the disk 2.

The power supply of the electric motor drive 22, which is pulse width modulated in the present case, takes place in a simple manner via a cable connection to the camera and its energy supply.

The installation of the presented lens attachment device 1 is very simple using the shown screw connections. A replacement of the disk 2 is also correspondingly simple in that the rear cover 8 is simply removed so that the holding frame 4 with the guided disk 2 can be simply released from the motor housing 26 and can be replaced by another holding frame with another disk.

The embodiment in accordance with FIG. 2 to FIG. 6 differs from the embodiment of FIG. 1 in the housing design and holding frame design, with the width of the motor housing 26 being narrower in the second embodiment.

In addition, a three-point support with buffers 30 is provided for the rotor of the electric motor 22. The buffers 30 cushion the carrier board 24 which receives the electric motor 22 so that a vibration damping of the electric motor 22 is achieved.

The drive wheel 20 for the disk 2 is thereby in turn cushioned so that true-running inaccuracies or inaccuracies of the total system of electric motor 22, disk 2 and the guide wheels 12, of which here the upper guide wheels have an eccentric bearing allowing tolerance compensations, are compensated.

In the third embodiment in accordance with FIG. 7, in which the disk 2 is not shown, the holding frame 4 of the disk 2 is made with connection devices 24, 36 which other modules 40 of the matte box have for connection to one another. The lens attachment device 1″ itself is thus a module insertable at any desired position and forming the matte box.

The connection devices are made as dovetail devices 34, 36 in the present case.

Although the shown embodiments have a cover glass disk 2, the use of a disk achieving an optical effect is also possible with the frame shown with a corresponding adaptation of the drive. 

14-27. (canceled)
 28. A lens attachment device for use with a matte box for a camera, the matte box including a filter holder configured to receive at least one filter therein, the lens attachment device comprising: a holding frame adapted to fit into the filter holder of the matte box; a transparent disk supported for rotation on the holding frame; and a drive operable to rotate the transparent disk with respect to the holding frame; wherein the lens attachment device is a lens protection device for protecting a lens from approaching particles.
 29. The lens attachment device as set forth in claim 28, wherein the transparent disk has a rim the drive being an electromagnetic drive having a drive wheel driving the rim of the disk, the electromagnetic drive being integrated into the holding frame.
 30. The lens attachment device as set forth in claim 29, wherein the electromagnetic drive is resiliently supported on the holding frame.
 31. The lens attachment device as set forth in claim 28, wherein the transparent disk is a neutral cover glass disk.
 32. The lens attachment device as set forth in claim 28, wherein the transparent disk is a disk providing an optical effect.
 33. The lens attachment device as set forth in claim 33, wherein the transparent disk is an optical filter.
 34. The lens attachment device as set forth in claim 34, wherein the optical filter is a polarization filter.
 35. The lens attachment device as set forth in claim 28, wherein the transparent disk is a first disk, the lens attachment device further comprising at least a second disk supported on the holding frame.
 36. The lens attachment device as set forth in claim 35, wherein the first disk and the second disk are polarization filters, the lens attachment device further comprising an additional drive operable to drive the second disk in a direction opposite the first disk.
 37. The lens attachment device as set forth in claim 28, further comprising a plurality of guide wheels on the holding frame each contacting and supporting the transparent disk, the guide wheels being generally uniformly distributed about the perimeter of the disk.
 38. A lens attachment device for use with a matte box for a camera, the matte box having a modular structure and being configured to receive interconnectable modules therein, the lens attachment device comprising: a holding frame configured as a module to be received into the matte box, the holding frame having a front side and a rear side, the holding frame having connection devices for connecting one of the front or rear sides of the holding frame to other modules in the matte box; a transparent disk supported for rotation on the holding frame; and a drive operable to rotate the transparent disk with respect to the holding frame wherein the lens attachment device is a lens protection device for protecting a lens from approaching particles.
 39. The lens attachment device as set forth in claim 38, wherein the transparent disk has a rim, the drive being an electromagnetic drive having a drive wheel driving the rim of the disk, the electromagnetic drive being integrated into the holding frame.
 40. The lens attachment device as set forth in claim 39, wherein the electromagnetic drive is resiliently supported on the holding frame.
 41. The lens attachment device as set forth in claim 38, wherein the transparent disk is a neutral cover glass disk.
 42. The lens attachment device as set forth in claim 38, wherein the transparent disk is a disk providing an optical effect.
 43. The lens attachment device as set forth in claim 42, wherein the transparent disk is an optical filter.
 44. The lens attachment device as set forth in claim 43, wherein the optical filter is a polarization filter.
 45. The lens attachment device as set forth in claim 38, wherein the transparent disk is a first disk, the lens attachment device further comprising at least a second disk supported on the holding frame.
 46. The lens attachment device as set forth in claim 45, wherein the first disk and the second disk are polarization filters, the lens attachment device further comprising an additional drive operable to drive the second disk in a direction opposite the first disk.
 47. The lens attachment device as set forth in claim 38, further comprising a plurality of guide wheels on the holding frame each contacting and supporting the transparent disk, the guide wheels being generally uniformly distributed about the perimeter of the disk. 